4 Weight Measurement

4.1 Introduction

Similar to the height measurement, the weight measurement is an
indicator of and can predict the nutritional status and health of a
population. When used in conjunction with the height measurement it
can be used to derive the Body Mass Index, a statistical measure
used to determine if an individual's weight falls within a healthy
range.

4.2 Exclusion criteria

Participants are excluded from this measurement if they are:

Pregnant

If the woman wishes to be weighed, you can but do not enter
the results into the computer.

Too frail or unable to stand upright

If you are concerned that being on the scales may cause them
to be too unsteady on their feet then do not weigh them.
Alternatively you can place the scales next to something that
they can steady themselves on.

Over 130kg (20 ½ stone) in weight as the maximum
weight registering accurately on the scales is 130kg. If you
think that the Participant exceeds this limit then code it
appropriately in
CAPI
and follow the prompts. Do not attempt to weigh them.

4.3 Equipment

There are different sets of scales in circulation on NatCen
projects. You will be provided with either:

Tanita THD-305 scales

The weight is displayed in a window on the scales. The scales
are switched on by pressing the button on the bottom right hand
corner of the scales. They are battery operated and require four
1.5v
AA batteries,
which should be sent with the scales. They may be packed separately
or one of the batteries may be turned around, to prevent the
batteries from going flat, as there is no on/off switch. Ensure
that you have spare batteries, just in case you need them.

Seca 877 scales

The weight is displayed in a window on the scales. The scales
are switched on by briefly covering the solar cell (for no more
than one second). The solar cell is on the right hand side of the
weight display panel.
NB You may experience
difficulties switching the scales on if there is insufficient light
for the solar cell. Make sure that the room is well lit. The scales
have a fixed battery which cannot be removed.

Please check which scales you have been provided with and make
sure that you are familiar with how they operate.

You will also need a pack of Milton antibacterial wipes.

4.3.1 Calibrating the scales

The scales will need to be sent to Brentwood at regular
intervals to be recalibrated to ensure that they provide accurate
measurements.
On each set of scales there is a label with a date that
they need to be recalibrated by, ensure that they have been sent to
Brentwood by this date.

4.3.2 Technical faults

Please refer to Table 1 when experiencing technical difficulties
with the scales.

Table 1 Troubleshooting for the scales

Fault

Action

Tanita THD 305 scales

No row of 8s when turned on or will not turn on

Replace batteries

If not solved, report to manager/Brentwood

Inconsistent readings

Make sure on hard flooring

Ensure 0.0 on display when Participant

steps on scales

Replace batteries

If not solved, report to manager/Brentwood

Seca 870 scales

No '1888' when turned on or will not turn on

Insufficient light to operate solar cell

If not solved, report to manager/Brentwood

Inconsistent readings

Make sure on hard flooring

Ensure 0.0 on display when Participant

steps on scales

Insufficient light to operate solar cell

If not solved, report to manager/Brentwood

4.4 Procedure for adults

1. Weigh the Participant on a hard and even surface if possible.
Carpets may affect measurements.

2. Ask the Participant to remove shoes, heavy outer garments
such as jackets and cardigans, heavy jewellery, and to empty their
pockets of all items.

3. Switch on the scales and wait for 888.8 (for the Tanita
scales) or 1888 (for the Seca scales) to be momentarily displayed
in the window. Do not attempt to weigh anyone at this point.

4. When the display reads 0.0, ask the Participant to stand with
their feet together in the centre and their heels against the back
edge of the scales. Their arms should be hanging loosely at their
sides and their head should be facing forward. Having the
Participant stand in this position means that the most accurate
weight measurement can be obtained. Ensure that they keep looking
ahead - it may be tempting for the Participant to look down at
their weight reading. Ask them not to do this and assure them that
you will tell them their weight afterwards if they want to
know.

5. The scales will need to stabilise. The weight reading will
flash on and off when it has stabilised. If the Participant moves
excessively while the scales are stabilising you may get a false
reading. If you think this is the case reweigh the Participant.

The scales are calibrated in kilograms and 100 gram units (0.1
kg). Record the reading in
CAPI
before the Participant steps off the scales.

7. If the Participant wishes, record the reading on their
measurement record card.

8. The scales should switch off automatically a few seconds
after the Participant steps off them.

9. Before packing the scales away ensure the footplate is wiped
again to reduce potential cross infection between households.

4.5 Procedure for children

1. You must get the co-operation of an adult household member.
This will help the child to relax and children, especially small
children are much more likely to be co-operative themselves if an
adult known to them is involved in the procedure.

2. Children who wear nappies should be dry. If the nappy is wet,
please ask the parent to change it for a dry one and explain that
the wetness of the nappy will affect the weight measurement.

3. Weigh the child, following the same procedure for adults.
Encourage the child to 'Be as still as a statue' for an accurate
reading. If you think that the results are inaccurate, code this in
CAPI.

For very young children who are unable to stand unaided or small
children who find this difficult follow the procedure below you
will need to ask for the assistance of an adult as the following
procedure requires you to measure the adult and then the adult
holding the child:

1. Explain to the adult what you are going to do and the reasons
why.

2. Code in
CAPI the
procedure used to measure the weight of the child.

3. Weigh the adult as normal following the protocol as set out
above. Enter this weight into
CAPI.

4. Weigh the adult and child together and enter this into
CAPI.CAPI will
calculate the difference between the two weights to get the child's
weight.

5. If the Participant wishes record this reading on their
measurement record card.

6. Before packing the scales away ensure the footplate is wiped
again to reduce potential cross infection between households.